TROCAR WITH REPLACEABLE OBTURATOR

Abstract: A kit assembly for use to construct a desired trocar obturator used during a surgical procedure is disclosed. The kit includes a proximal portion of the obturator and a plurality of different distal end portions. The proximal portion may be releasably attached to a distal portion by virtue of a detent mechanism. Reuse of the proximal portion affords potential cost savings. The plurality of distal end portions affords the surgeon a choice between different trocar tips so that the trocar may be customized for a particularly surgical procedure.

Description: TROCAR WITH REPLACEABLE OBTURATOR Technical Field The present invention is directed to trocars for inserting an access tube or "cannula" through an abdominal wall, and more particularly to a reusable trocar having an easily replaceable obturator portion. Background of the Invention An increasing number of abdominal surgical procedures are being performed with laparoscopic techniques in order to avoid a large skin incision. Typically in laparoscopic surgery, a special needle, similar to the pneumoneedles described in U.S. Patent No. 4,808,168 to Warring and U.S. Patent Application No. 07/808,152 (both of which are herein expressly incorporated by reference) , is inserted through the skin, and used to inflate the abdominal cavity with an insufflating gas such as C0 2 . Once the abdomen is adequately dilated, the needle is removed and a rigid access tube or cannula with a larger diameter (for example 10 or 11 mm) is passed through the skin in the same location. The access tube provides access for laparoscopes or other laparoscopic surgical tools such as the stapler described in U.S. Patent No. 5,040,715 or the surgical clip appliers described in U.S. Patent No.'s 5,084,057 and 5,100,420. To drive the access tube through the skin, the surgeon places a trocar obturator in the lumen of the access tube to provide a sharp, leading edge for cutting tissue. The art is replete with trocar devices such as those shown in U.S. Patent No's. 4,535,773, 4,601,710, 4,654,030, 4,902,280, and 4,931,042. A prior art trocar device typically comprises a sharp point for penetrating the skin, surrounded by a spring-loaded protective sleeve. As these trocar devices are urged through the skin, friction with the skin causes the protective sleeve to slide proximally (rearwardly) . After the access tube has penetrated through the skin, there is no longer friction between the protective sleeve and the skin, and the spring is designed to urge the protective sleeve distally (forwardly) to cover the sharp point, locking the protective sleeve in position to reduce the risk of accidental puncture of the underlying organs. Two typical "safety" trocars currently available are known as the "Auto Suture Surgiport" T.M. (generally available from U.S. Surgical of Norwalk, Connecticut) and the "Endopath" T.M. (generally available from Ethicon of Somerville, N.J.). Trocars similar, but not identical to these are shown in U.S. Patents 5,066,288 and 5,030,206. These types of prior art trocar devices are generally used during a surgical procedure and then disposed of after the surgical procedure is completed. Such prior art trocars tend to be expensive and complicated, particularly when a "safety" mechanism is included. Also, the presence of a shield or protective sleeve necessarily reduces the size of the obturator/knife used with a given size of cannula and may cause other problems for the user or patient. A more cost effective alternative to a disposable trocar is a completely reusable trocar, such as the Trocars generally available from Snowden-Pencer, Inc. of Tucker, Georgia or the Trocars generally available from Solos, Endoscopy, Inc. of Duluth Georgia. A reusable trocar typically comprises an obturator assembly having sharp surfaces for cutting tissue, and a cannula or access tube assembly. The obturator assembly of a typical reusable trocar may be used on a patient and then cleaned and sterilized for reuse on the same or a different patient. Reusable trocars tend to have minimal parts to afford quick and convenient cleaning and sterilization of the trocars. Reusable trocars tend to encounter problems as the sharp tissue cutting surfaces of the obturator (including the tip) of a completely reusable trocar tend to become dull after even a few uses. Such dulling of the cutting surfaces of the trocar generally tends to increase the insertion force required to insert the trocar into the abdominal cavity. Additionally, the sharp tissue cutting surfaces of a reusable trocar are vulnerable to mechanical damage from mishandling or other abuse during cleaning, sterilization and handling. For example, if the cutting surfaces or tip of a reusable trocar impulsively impact a solid object (such as when the obturator is inadvertently dropped on the floor or working area) , the tip of the obturator tends to take a highly undesirable "hook" shape. U.S. Patent No. 4,601,710 discloses a trocar assembly having a trocar tip attached to the rest of the trocar assembly by set screws or threads. Also, AeSclepios Surgical Endoscopy, Inc. of Montreal, Quebec Canada and General Medical of Richmond Virginia are believed to currently sell a reusable trocar having a trocar tip that is attached to the rest of the trocar assembly by threads. Threading the trocar tip to the rest of the trocar assembly is believed to be undesirable because it may be difficult for the user to determine when the trocar tip is completely screwed into the rest of the trocar assembly. Although some surgeons prefer that the trocar tip slightly rotate relative to the cannula during insertion, some surgeons prefer that the trocar tip remain stationary relative to the cannula during insertion. If the trocar is used when the trocar tip is not completely screwed into the rest of the trocar assembly, the trocar tip may rotate relative to the rest of the trocar assembly and the cannula. Again, some surgeons wish to avoid such action. Also, the threaded portion of such a trocar is believed to be difficult to clean or sterilize as in some procedures, it may expose a healthcare worker to relatively sharp threaded surfaces that may be contaminated. Using a set screw to attach the trocar tip to the rest of the trocar assembly is believed to be cumbersome or difficult for the user, as a user is required to manipulate a potentially fine set screw. Finally, the art iε replete with various types of designs for the distal ends of trocars used during laparoscopic surgical procedures. Examples of distal ends of trocars include pyramidal (with at least three cutting surfaces) , elliptical-shaped, blunt (known in the art as Hasson-type obturators) , and conical or frusto-conical shaped. However, when a trocar with a particular distal end is disposed of, both the proximal and distal end of the trocar are disposed of resulting in unnecessary waste with attendant cost disadvantages. Brief Description of the Invention According to the present invention there is provided a reusable trocar assembly which (1) affords sharp cutting surfaces even after repeated trocar uses, (2) has an obturator having a proximal portion and a distal end portion with sharp surfaces for cutting tissue, (3) affords firm retention of the distal end portion by the proximal portion while the obturator is inserted and removed from the patient's body, but which also affords easy convenient release of the distal end portion from the proximal portion to afford replacement of the used or dull distal end portion, (4) affords convenient and efficient disposal and replacement of a used or dull obturator distal end portion, (5) optionally includes a mechanism for releasing the distal end portion without requiring a user to grasp the distal end portion, (6) is inexpensive and easy to manufacture, (7) affords convenient, rapid sterilization and cleaning of its reusable portions, (8) which is convenient and simple to use, (9) which may be provided in a kit assembly that affords the use of a plurality of different types or styles of distal end portions with the same proximal portion with potential cost-savings and simplification of cleaning and sterilization procedures. The present invention comprises a trocar assembly for placement in a cannula to facilitate inserting the cannula through a wall having tissue defining a body cavity. The cannula comprises interior surfaces defining a lumen and a distal end having an opening. The trocar assembly comprises a handle, and an obturator having an imaginary axis. The obturator comprises a proximal portion, and a distal end portion comprising a base part. This distal end portion has cutting surfaces adapted to pierce the wall defining the body cavity. The trocar assembly also comprises detent means for releasably connecting, the proximal portion of the obturator to the distal end portion of the obturator. The detent means comprises a groove part extending at least partially about the axis of the obturator located on one of the proximal and distal end portions and a detent part situated on the other of the proximal and distal end portions and adapted to engage the groove part. When the obturator is placed within the cannula, at least a portion of the groove part and the detent part are situated within the lumen of the cannula and the cutting surfaces project beyond the distal end of the cannula. In this configuration the detent part is "locked" to the groove part to restrict the chances of the distal end portion of the obturator falling into the patient. Several species of trocar assemblies are shown and described. The trocar assemblies have various features. For example, a first embodiment of trocar assembly comprises means for restricting relative rotation between the distal end portion and the proximal portion comprising leaf spring members and ribs which mesh. Both the first and a second embodiments of trocar assembly describe different means for releasing the distal end portion without requiring the user to grasp the distal end portion. The first embodiment describes an ejector rod having a distal end adapted to abut a proximal end of the distal end portion, and a button member mounted to the ejector rod and movable between a release and a rest position. The second embodiment of trocar assembly describes a disposal container having first and second sections each having manually engagable outer surfaces and trocar distal end portion engaging surfaces. The disposal container's first and second portions are movable between an open position adapted to receive a distal end portion of a trocar assembly and a closed position. In the closed position (1) the distal end portion engaging surfaces grasp portions of the distal end portion of the obturator, (2) the disposal container encloses the cutting surfaces of the distal end portion and provides a barrier to restrict the user's exposure to the cutting surfaces, and (3) a user may grasp the manually engagable surfaces of the disposal container and move the disposal container axially away from the proximal portion of the trocar assembly to separate the distal end portion from the proximal portion. In a third embodiment of the present invention, the detent means comprises a lug. In a fourth embodiment of the present invention, there is provided a kit assembly having a proximal portion and a plurality of distal end portions for use with the proximal portion. The kit assembly provides a reduction of waste in that for a plurality of obturators used during a laparoscopic surgical procedure, only one proximal portion needs to be used. Attendant cost saving advantages are believed present with this approach as well. Also, the kit assembly provides trocars to surgeons in a convenient manner, and the surgeon may assemble the trocar according to their preferences. Brief Description of the Drawings The present invention will be further described with reference to the accompanying drawing wherein like reference numerals refer to like parts in the several views, and wherein: Figure 1 is a perspective view of a first embodiment of trocar assembly according to the present invention that is placed within a cannula assembly that includes a valve which affords passage of insufflating gas into the body cavity and which restricts loss of insufflating gas from the body cavity when the trocar assembly is removed from the cannula assembly; Figure 2 is a slightly enlarged sectional view of the trocar and cannula assemblies shown in Figure 1 with portions broken away or omitted to show details; Figure 3 is an exploded, enlarged perspective view of portions of the cannula assembly of Figure l; Figure 4 is an enlarged sectional view of the first embodiment of trocar assembly and the cannula assembly shown in Figure 2, taken approximately along lines 4-4 of Figure 2; Figure 5 is a sectional view of the trocar assembly of Figure 1 removed from the cannula assembly and illustrating an obturator distal end portion being released into a disposal container and with portions broken away to emphasize details; Figure 5A is a sectional view of the trocar assembly of Figure 1 removed from the cannula assembly and illustrating an obturator distal end portion that is released into a disposal container; Figure 6 is a side view which illustrates a rack of replacement distal end portions; Figure 7 is a sectional view of a second embodiment of trocar assembly according to the present invention and a cannula assembly; Figures 8 and 9 are perspective views of a disposal container which sequentially illustrates the removal of a used or dull obturator distal end portion for the embodiment of trocar assembly shown in Figure 7 wherein: Figure 8 is a perspective view of the disposal container with a portion of the obturator distal end portion (of the trocar assembly of Figure 7) placed within the disposal container, and which omits details of the detent means to emphasize other details; Figure 9 is a perspective view of the disposal container closed about the obturator distal end portion and with the obturator's proximal portion separated from the obturator's distal end portion; Figure 10 is a side view of an obturator's distal end portion with a conical cutting portion; Figure 11 is a top view of a portion of a third embodiment of trocar assembly according to the present invention illustrating the distal end portion of the obturator; Figure 12 is a top view of another portion of a third embodiment of trocar assembly according to the present invention illustrating the proximal end portion of the obturator and with portions broken away to show details; Figure 13 is a side view of the distal end portion shown in Figure 11 taken approximately ninety (90) degrees from that view; Figure 14 is a side view of the proximal end portion of Figure 12 taken approximately ninety (90) degrees from that view; Figure 15 is a side view of a proximal portion and a plurality of different styles or types of distal end portions according to a fourth embodiment of the present invention; and Figure 16 is a top view of a kit according to the fourth embodiment of the present invention which illustrates a proximal portion of a trocar assembly packaged with a plurality of different styles or types of distal end portions. Detailed Description of the Preferred Embodiment Referring now to Figures 1, 2 and 4 and 5 of the drawing there is shown an embodiment of a trocar device or assembly generally designated by reference character 10. The trocar assembly 10 is preferably used in laparoscopic surgery, however, the trocars described herein may also be used in other surgeries such as orthopedic surgery or in closed wound drainage applications. Figure 1 illustrates the trocar assembly 10 placed within a cannula assembly 9 which includes a cannula 2. The trocar assembly 10 may be completely removed from the cannula assembly 9 by sliding the trocar assembly 10 longitudinally relative to the cannula assembly 9. The trocar assembly 10 is adapted for placement within the cannula 2 to facilitate inserting the cannula 2 through a wall 4 (Figure 2) having tissue defining a body cavity 6. For example the trocar assembly 10 may be used to insert an access tube or cannula 2 through an abdominal wall of a patient. The cannula 2 comprises interior surfaces 3 defining a lumen and a distal end 5 having an opening. The cannula 2 has an enlarged fixture formed from left and right portions 42 and 43. The fixture has a chamber at its proximal end. There is an opening at the proximal end of the chamber through which the trocar fits while the cannula 2 is inserted in the body cavity, and through which surgical instruments can access the interior of the body cavity after the cannula 2 is in place and the trocar assembly is removed. Figure 3 is an exploded perspective view of the cannula assembly 9. The cannula assembly 9 is the type which affords passage of insufflation gas through valve 41 to inflate the abdominal cavity and which restricts the passage of insufflation gas from the abdominal cavity after the trocar assembly 10 has been removed from the cannula assembly 9. The cannula assembly 9 is similar to the cannula assembly described in U.S. Patent No. 5,152,754. As best seen in Figure 3, the cannula assembly 9 includes first 42 and second 43 housing or handle portions which may be assembled by a snap fit with a suitable adhesive (e.g. a "Prism" T.M. Loctite adhesive generally available from Loctite corporation of Newington, Connecticut) to form a chamber 44. There is an opening at the proximal end of the chamber 44 through which the trocar fits while the access tube or cannula 2 is inserted in the body cavity, and through which surgical instruments can access the interior of the body cavity after the cannula 2 is in place and the trocar is removed. A trap door valve member 48 having a sealing gasket is pivotally mounted adjacent the opening to close the opening. The valve member 48 is operated by a pushbutton 45 mounted for movement relative to first and second handle portions 42, 43. The pushbutton 45 is reciprocally mounted in a sealing gasket 46, and is resiliently spring biased outwardly by spring 47. A link 49 extends from the pushbutton 45 to the valve member 48. Manually pushing the pushbutton 45 inwardly moves the valve member 48 open. The bias of the spring 47 causes the button 45 to move outwardly when it is release thereby causing the valve member 48 to close. The cannula assembly 9 also includes an insertion funnel guide adapter 37, an adapter seal stabilizer 34 and an O-ring 40. The trocar assembly 10 comprises a handle 11 with a generally rounded configuration that can be comfortably gripped by the user. The handle 11 may be placed adjacent the chamber in the cannula assembly 9, and may comprise first and second polymeric portions which may be assembled by a snap fit with a suitable adhesive (e.g. a suitable "Prism" T.M. Loctite adhesive generally available from Loctite Corporation of Newington, Connecticut) . The handle 11 is releasably, frictionally attached to the cannula assembly 9 so that after the trocar 10 inserts the cannula 2 in the wall 4, the trocar 10 can be removed so that the cannula 2 can be used to introduce surgical instruments (e.g. such as a clip applier or stapler) into the body cavity. The handle 11 optionally includes flanges F which cooperate with grooves on the first and second portions 42 and 43 to restrict relative rotation between the handle 11 and the cannula assembly 9. The trocar assembly 10 also includes an obturator 12 extending from the handle 11 and having an imaginary axis A (Figure 1) . The obturator 12 comprises a proximal portion 14, and a distal end portion 15 comprising a base part 16 and having three generally planar surfaces 17 intersecting to form three cutting edges and a point 18 at the distal end of the obturator 12 adapted to pierce the wall 4. Figure 10 illustrates an alternative form of distal end portion 15' which includes a conical portion with a point 18'. Generally, the distal shape of the cutting surfaces of the obturator may take any suitable shape such as but not limited to triangular or square based pyramids or hollow parabolic, as long as the obturator is adapted to cut tissue. Additional alternative forms of the distal end portion are described in conjunction with the embodiment of the present invention shown in Figures 15 and 16. The trocar assembly 10 also includes detent means 20 for releasably connecting the proximal portion 14 of the obturator to the distal end portion 15 of the obturator 12 and optionally for restricting relative rotation between the distal end portion 15 and the proximal portion 14. The detent means 20 comprises a groove part 22 extending at least partially about the axis A of the obturator 12 located on one of the proximal 14 and distal end 15 portions (in the species shown in Figures 1, 2, 4 and 5, the groove part 22 is located on the distal end portion 15) and a detent part 24 situated on the other of the proximal 14 and distal end 15 portions (in the species shown in Figures 1, 2, 4 and 5, the detent part 24 is located on the proximal part 14) . The detent part 24 is adapted to releasably engage the groove part 22. When the obturator 12 is placed within the cannula 2 , the groove part 22 and the detent part 24 are situated within the lumen of the cannula 2 and the cutting edges project beyond the distal end 5 of the cannula 2 (see Figure 2) . As best seen in Figure 2, 4 and 5, the detent means 20 comprises a plurality of detent parts 24 having leaf spring members 27 movable radially outwardly (see Figure 5) to accept or release the groove part 22 on the distal end portion 15. When the trocar assembly 10 is placed within the cannula 2, the interior or inside surfaces 3 defining the cannula lumen prevent the leaf spring members 27 from moving or deflecting radially outwardly to prevent release of the distal end portion 15 from the proximal portion 14. This prevents the distal end portion 15 from being accidently or inadvertently dropped into the body cavity 6 during a surgical procedure. As shown in Figures 2, 4 and 5, the proximal portion 14 may comprise a housing member 26 constructed from any suitable material such as stainless steel, a polycarbonate or polypropylene. The proximal portion 14 also includes the leaf spring members 27 (which has the detent 24) which may be constructed from any suitable, flexible material such as, but not limited to a stainless steel, polycarbonate or polypropylene. The leaf spring members 27 may be adhesively attached to the housing member 26. The leaf spring members 27 should be flexible enough to afford radially outward movement so that the distal end portion 15 may be received and yet resilient enough to allow the detent part 24 to spring back into engagement with the groove 22. The distal end portion 15 may be constructed from any suitable material such as but not limited to a stainless steel, polycarbonate or polypropylene. Aluminum may also be used to construct the distal end portion 15. Since, the distal end portion is disposable, the material used to construct the distal end portion 15 is preferably inexpensive yet affords construction of sufficiently sharp and durable cutting surfaces. As best seen in Figure 4, the groove part 22 includes a plurality of axially extending ribs 25. When the proximal portion 14 is attached to the distal end portion 15 (as shown in Figures 1 and 4) , the ribs 25 are situated between the leaf spring members 27 to restrict relative rotation between the proximal 14 and distal end 15 portions, and also between the distal end portion 15 and the cannula 2. Alternatively, the ribs 25 may be completely omitted from the embodiment shown in Figures l, 2, 4 and 5. Optionally, the trocar assembly 10 further includes means 30 for releasing the distal end portion 15 without requiring the user to grasp the distal end portion 15. The means 30 comprises the distal end portion 15 having camming surfaces 31, and the proximal portion 14 having bearing surfaces 32. The means 30 also includes an ejector rod 35 at least partially located within the proximal portion 14. The ejector rod 35 is axially movable relative to the proximal portion 14. The ejector rod 35 has a distal end 36 adapted to abut a proximal end 19 of the distal end portion 15. The means 30 also includes a button member 38 mounted to the ejector rod 35. The button member 38 iε axially movable between release (Figure 5A) and rest/graεp (Figure 2) positionε. Between the reεt/graεp and the release positions, the leaf spring members 27 deflect radially outwardly relative to the axis A taking the detent parts 24 out of engagement with the groove parts 22 to afford passage and release of the distal end portion 15 (see Figure 5) . A biasing means in the form of a coil spring 39 biases the button member 38 toward the rest position. When the trocar asεe bly 10 iε removed from the cannula 2, the button member 38 may be moved from the graεp to the release position so that the camming surfaces 31 may engage the bearing surfaces 32 and move portions of the leaf spring members 27 radially outwardly to releaεe the diεtal end portion 15 (Figure 5) . It should be noted that when the trocar assembly is located within the cannula assembly 9, the interior surfaces 3 of the cannula 2 prevent the leaf spring members 27 from deflecting radially outwardly. Figure 6 illustrates a rack 28 of replacement distal end portions which may optionally include a cover 29. When the cover 29 is removed, the rack 28 exposes the proximal end 19 of a plurality of the replacement distal end portions 15 so that a user may conveniently slide the proximal end portion 14 onto the distal end portion 15 so that the detent part 24 engages the groove part 22. The rack 28 may include diverse distal end designs (e.g. distal tips with different shaped cutting surfaces such as conical, pyramidal etc.) according to the needs of a particular surgical procedure. Operation The trocar assembly 10 will be used to describe a method according to the present invention. The trocar assembly 10 optionally includes a protective cap (not εhown) over the point 18 that is removed prior to use of the trocar assembly 10. The cannula 2 is initially installed over the distal end of the trocar assembly 10. The user grasps the handle 11 and first and second portions 42 and 43 of the trocar and cannula assemblies 9 and 10 with the palm of the hand. The trocar assembly 10 is then advanced against the wall 4 of a patient (Figure 2) . The user continues to advance the trocar assembly 10 until the wall 4 is penetrated. As the wall 4 is being penetrated, the interior surfaces 3 of cannula 2 prevents the leaf spring parts 27 from springing radially outwardly to restrict the opportunity for the distal end portion 15 from inadvertently or accidently falling into the abdominal cavity 6. Once the cannula 2 has penetrated through the wall 4, the user may then grasp the first and second portions 42 and 43 of the cannula assembly 9, and pull the trocar handle 11 axially and proximally relative to the cannula 2, leaving the cannula 2 in the abdominal wall 4. As noted above, the cannula assembly 9 may have a trap-door valve that closes the cannula 2 when the trocar is withdrawn to prevent the escape of insufflation gas from the abdomen. The trocar 10 can be quickly prepared for reuse (on the same patient) by pressing the button member 38 and allowing the used distal end portion 15 to fall into a disposal container 7 (Figures 5 and 5A) , and then snapping another, replacement distal end portion 15 with sharp cutting surfaces onto the proximal portion 14. Optionally, the trocar assembly 10 may be sterilized, if necessary, by techniques well known in the art such aε Gamma Radiation, steam or Ethylene Oxide (EtO) gas sterilization. Another cannula 2 can then be placed over the trocar assembly 10, and the procedure repeated on the same or a different patient. Thiε procedure affords a clean, sharp distal tip end portion 15 which requires minimal handling by medical personnel. Referring now to Figures 7, 8 and 9 of the drawing, there is εhown a εecond alternative embodiment of trocar assembly according to the present invention, generally designated by the reference character 50. The assembly shown in Figure 7 includes the trocar assembly 50 and a cannula asεembly 9A (including cannula 2A) . Unlike the cannula assembly 9, the cannula asεembly 9A doeε not include a trap door for preventing the eεcape of insufflating gas. The trocar assembly 50 has many elements which are essentially the same or identical as elementε in the trocar assembly 10 which are identified by the same reference character to which the suffix "A" has been added. The trocar assembly 50 comprises a handle 11A that is releasably, frictionally attached to the cannula assembly 9A. The trocar asεembly 50 also includes an obturator 12A extending from the handle 11A. The obturator 12A comprises a proximal portion 14A, and a distal end portion 15A comprising a baεe part 16A and having three generally planar εurfaceε 17A intersecting to form three cutting edges and a point 18A. Optionally, the trocar assembly 50 may include a cleanout or flush channel extending between the inner surfaces of the obturator 12A and a proximal end of the handle 11A. The trocar assembly 50 also includes detent means 20A for releasably connecting the proximal portion 14A of the obturator to the distal end portion 15A of the obturator 12A. The detent meanε 20A comprises a groove part 22A located on one of the proximal 14A and distal end 15A portions and a detent part 24A situated on the other of the proximal 14A and distal end 15A portions. The detent means 20A compriseε a plurality of detent parts 24A having leaf εpring memberε 27A movable radially outwardly to accept or release the groove part 22A on the distal end portion 15A. When the trocar assembly 50 is placed within the cannula 2A, the interior or inside surfaces 3A defining the cannula lumen prevent any portion of the leaf spring members 27A from moving or deflecting radially outwardly, and thus prevent release of the distal end portion 15A from the proximal portion 14A. Unlike the trocar assembly 10, the trocar assembly 50 does not include the means 30. Instead the trocar asεembly 50 uεeε engagable surfaces 51 located on the distal end portion 15A. For example, a uεer may manually engage the εurfaceε 51 and εimply pull the proximal portion 14A axially relative to the diεtal end portion 15A to remove a uεed or dull diεtal end portion. Alεo unlike the trocar assembly 10 and as best seen in Figure 9, the distal portion 15A of the obturator 12A does not include ribs 25 and instead has a cylindrical portion 53. The detents 24 and the leaf spring members 27A are not obstructed and thus, the distal portion 15A iε free to rotate relative to the cannula 2A and proximal portion 14A to afford a "drilling action" preferred by some surgeons. The engagable surfaceε 51 are εpaced from the cutting edges and are adapted to be grasped by a uεer. When the trocar aεεembly 50 is removed from the cannula, a user may manually grasp the distal end portion 15A by the engagable surfaces 51 and pull the distal end portion 15A away from the proximal portion 14A to cause the leaf spring members 27A to move radially outwardly to releaεe the diεtal end portion 15. Figureε 8 through 9 illuεtrate an alternative, preferred method of removing the diεtal end portion 15A from the proximal portion 14A of the trocar aεεembly 50 which includes a means for releasing the distal end portion without requiring the user to grasp the distal end portion generally designated by reference character 52. The means 52 comprises a disposal container having first 56 and εecond 57 εectionε each having manually engagable outer surfaces 58 and distal end portion engaging surfaces 59 spaced from the manually engagable outer surfaceε 58. The diεposal container includes hinge 55 and latch 60. The dispoεal container iε preferably integrally conεtructed from an inexpenεive material such as, but not limited to a polycarbonate, so long as it acts as a barrier to prevent the cutting surfaces of the obturator from coming into contact with a person (e.g. εuch aε a surgeon or processor of medical waste) . The dispoεal container'ε firεt 56 and second 57 portions are movable between an open position (Figure 8) where they receive a distal end portion 15A of trocar assembly 50 and a closed position (Figure 9) . In the cloεed position, (1) the distal end portion engaging surfaces 59 grasp portions of the distal end portion (e.g. the engagable surfaces 51) , (2) the dispoεal container encloεeε the cutting surfaces of the distal end portion 15A and provides a barrier to restrict exposure to the cutting εurfaceε, and (3) a user may grasp the manually engagable surfaceε 58 of the disposal container and move the dispoεal container axially away from the proximal portion 14A of the trocar aεεembly 50 to εeparate the distal end portion 15A from the proximal portion 14A without requiring the user to grasp the distal end portion 15A. Referring now to Figures 11 through 14 of the drawing, there is shown a third alternative embodiment of trocar assembly according to the present invention, generally designated by the reference character 100. The trocar assembly 100 is adapted for use with cannula asεemblieε εimilar to the cannula assemblies 9 and 9A. The trocar assembly 100 compriseε a handle (omitted to εhow detail but εimilar to 11 or 11A) that is releasably, frictionally attached to the cannula assembly. The trocar assembly 100 also includes an obturator 112 extending from the handle. The obturator 112 comprises a proximal portion 114, and a distal end portion 115 comprising a baεe part 116 and having three generally planar εurfaceε 117 interεecting to form three cutting edgeε and a point 118. Alternatively the cutting surfaces may comprise any suitable, desired εhape. The trocar aεεembly 100 alεo includeε detent meanε 120 for releaεably connecting the proximal portion 114 of the obturator to the distal end portion 115 of the obturator 112. The detent means 120 comprises a groove part 122 located on one of the proximal 114 and distal end 115 portions (in Figureε 12 and 14, the groove part 112 is shown on the proximal portion 114) and a detent part 124 situated on the other of the proximal 114 and distal end 115 portions (in Figures 11 and 13, the detent part 124 iε shown on the distal portion 115) . The detent part 124 comprises two lug portions 126 and 127. The lug portion 126 has a semicylindrical outer surface sharing an axiε with the axiε A' of the obturator 112. The lug portion 127 may alεo have a εemicylindrical outer εurface that doeε not εhare an axiε with the obturator 112, or alternatively, as shown in Figure 13, the lug portion 127 may simply be a flat surface. To construct the obturator 112, the distal end portion 115 would be placed into the proximal portion 114 from the side or top and then the obturator 112 would be placed within the lumen of a cannula assembly where the interior surfaces of the cannula assembly (e.g. 3 or 3A) would lock or secure the distal end portion in place. The lug 126 is believed to restrict or prevent rotation of the distal end portion 115 from rotating relative to the proximal portion or the cannula assembly. Referring now to Figures 15 and 16 of the drawing, there is shown a fourth alternative embodiment of the present invention, generally designed by the reference character 200. The kit assembly 200 is provided for uεe during a laparoεcopic εurgical procedure. The kit assembly 200 compriseε a proximal portion 201 of a obturator having a handle 202 adapted to be manually graεped, and attachment means for releasably connecting the proximal portion 201 of the obturator to a distal portion (discuεεed in greater detail below) . Exampleε of different diεtal portions are shown in Figure 15 as reference characters 210-216. Each of the distal portionε 210-216 are different from each other within the εcope of the preεent invention. Preferably, each of the distal portions have substantially the same outer diameter D (relative to a radius taken from the longitudinal axis) so that they may each fit through the same diameter cannula lumen. For example, each of the distal portions may fit through a 10 mm cannula. Distal end portion 210 comprises a conical shaped tip for cutting tissue. This distal portion is also shown in Figure 10. Conical tip trocars are preferred by some surgeons. A conical shaped tip on an obturator is shown in U.S. Patent No. 5,002,557, the entire contents of which are herein expressly incorporated by reference. Reference character 211 depicts a distal portion having a pyramid-shaped distal end. When it is said that the distal end portion is pyramid shaped, it is meant that the distal end portion has at least three substantially-planar face surfaces 231 situated at an angle relative to each other. The face surfaces 231 intersect at cutting surfaces 232 that are sharpened to cut tissue. The cutting surfaces 232 culminate in a sharp tip 233. Examples of obturators having pyramid- shaped cutting surfaceε are εhown in U.S. Patent No.'s 3,994,287, 4,177,814 and 5,152,754. Reference character 214 illustrates distal end comprising a customized pyramid-shaped distal end portion 214. The illustrated customized pyramid-shaped distal end portion 214 is known as a bilevel style obturator tip which iε conεidered to be quite εharp. Like the diεtal end portion 211, the diεtal end portion 214 has a plurality of planar face surfaceε 231, cutting εurfaceε 232 and a sharpened tip 233. However, unlike the distal end portion 211, the distal end portion 214 includes planar face surfaces 240 situated at a angle relative to the face surfaceε 231. Alternative exampleε of obturatorε that have cuεtomized pyramid-shaped distal end portions are shown in U.S. Patent No. 5,057,082, the entire contents of which are herein expresεly incorporated by reference. Distal portion 212 iε generally identical to distal portion 211 except that distal portion 211 is elongate along itε longitudinal axiε compared to distal portion 211. The elongate diεtal portion 211 iε believed to be particularly desirable for use in conjunction with an elongate cannula during a procedure on an obeεe patient to ensure that the trocar and cannula completely piece the abdominal wall. Distal portion 213 compriεes a blunt distal end 218. For example, the distal end may comprise a subεtantially εemi-εpherical εhaped εurface. Commercially, a blunt diεtal end trocar is commonly referred to as a Haεεon-type obturator and iε generally available from Snowden Pencer of Tucker, Georgia. Hasson-type cannula are diεcloεed in U.S. Patent No.'s 3,817,251 and 4,617,933. Distal portions 215 and 216 are further exampleε of different typeε of distal end portions according to the preεent invention. Distal portion 215 includes a cutting surface that is substantially perpendicular to the longitudinal axis of the diεtal portion, similar to the cutting εurface shown in Figure 1 of U.S. Patent No. 4,535,773. Distal portion 216 compriseε elliptical shaped cutting surfaceε 219. Obturators having elliptical-shaped cutting surfaceε are shown, for example, in U.S. Patent No.'s 5,104,382, 5,223,951, and 5,226,426. The proximal portion includes an attachment meanε for releasably attaching the proximal portion 201 to one of the distal portions 210-216. Each of the distal portions 210-216 include an means, cooperable with the attachment means, for releasably connecting them to the proximal portion 201. For example, distal portions 210 may each include a groove part 250 adapted to be releaεably engaged by a detent part (not εhown in Figure 15 and 16) on the proximal portion 201. The attachment meanε may comprise any of the detent means described above. According to one aspect of the present invention, the proximal portion 201 may be packaged separately from any distal portions. Such a kit allows surgeons to use a proximal portion with a desired distal portion. Thuε, the trocar iε aεεembled according to a εurgeon's preference rather than the dictates of the package. Example 1 With reference to Figure 16, the kit assembly 200 may comprise three diεtal portionε 211, 212 and 213 and one proximal portion 201 εituated within package 220. Alternatively, the package may compriεe the rack shown in Figure 6 except that the proximal portion 201 is added. The kit 200 may be uεed during a laparoscopic surgical procedure. Typically, the abdominal cavity is initially insufflated with a pneumoneedle. Next, a trocar εuch aε the trocar εhown in U.S. Patent 5,152,754 may be used to insert a cannula through which an endoscope may be threaded. The endoscope may reveal to the surgeon that a conventional pyramid-εhaped diεtal end portion 211 may be uεed to inεert a εecond cannula at one portion, but that becauεe of obeεity of the patient (for example) the elongate diεtal end portion 212 εhould be used to insert another cannula at a different point. Finally, due to patient senεitivity or other reasons, the endoscope may reveal that only a Hasson-type distal end portion 213 should be used to insert a cannula at a particular portion. It should be noted that at the end of such a procedure, only one proximal portion 201 need be disposed, thus providing the potential for cost savings and reduced waste. Alεo, requiring εterilization of only the proximal portion 201 may simplify sterilization procedures. The present invention has now been described with reference to several embodiments thereof. It will be apparent to those skilled in the art that many charges or additional can be made in the embodiments described without departing from the scope of the present invention. For example, the trocar assembly 50 may include ribs similar to the ribs 25 shown in Figure 4; and the cannula assembly 9A shown in Figure 7 may be replaced with a cannula assembly which is subεtantially identical to the cannula assembly 9 shown in conjunction with the first embodiment of trocar aεεembly 10 (e.g. it may include a trap door valve mechaniεm, etc.). Additionally the trocar assembly 10 may be used in conjunction with a cannula assembly similar to the cannula assembly 9A. Also, the detent part 24 of the trocar asεembly 10 may be located on the distal end portion 15 and the groove part 22 may be located on the proximal portion 14.

Claims: What is claimed is: 1. A kit aεεembly for uεe during a laparoεcopic surgical procedure comprising: a proximal portion of a trocar having a handle adapted to be manually graεped, and attachment meanε for releaεably connecting εaid proximal portion of εaid trocar to a diεtal portion; and a plurality of diεtal portionε compriεing: a firεt diεtal portion having a meanε, cooperable with said attachment means, for releasably connecting εaid first distal portion to εaid proximal portion, and a firεt diεtal end portion, and a second distal portion having a means, cooperable with said attachment means, for releaεably connecting said second distal portion to said proximal portion, and a second distal end portion which is different than said first distal end portion. 2. A kit assembly according to claim 1 wherein said first distal end portion comprises pyramidal- shaped cutting surfaceε, and said second distal end portion comprises a blunt surface. 3. A kit asεembly according to claim 1 wherein said first distal end portion comprises a conical- shaped cutting surface, and said second distal end portion compriεes an elliptical shaped cutting surface. 4. A kit asεembly comprising, a proximal portion of a trocar having a handle adapted to be manually grasped, and attachment means for releasably connecting said proximal portion of said trocar to a diεtal portion, a plurality of distal portionε compriεing: a first distal portion having a means, cooperable with εaid attachment meanε, for releasably connecting said first distal portion to said proximal portion, and a first distal end portion, and a second distal portion having a means, cooperable with said attachment means, for releaεably connecting said first distal portion to εaid proximal portion, and a second distal end portion which is different than εaid first distal end portion. 5. A kit assembly according to claim 4 wherein said first distal end portion compriseε pyramidal- shaped cutting surfaceε, and said second distal end portion comprises a blunt surface. 6. A kit assembly according to claim 4 wherein said first distal end portion comprises a conical- shaped cutting surface, and said second distal end portion comprises an elliptical shaped cutting surface. 7. A kit aεsembly according to claim 4 further comprising a package which presents the first and second distal portions in a manner which affords attachment to the proximal portion without requiring a user to grasp the distal end portion. 8. A kit aεεembly according to claim 7 wherein the package compriεes a rack. 9. A kit aεεembly compriεing: a trocar aεεembly for placement in a cannula to facilitate inserting the cannula through a wall having tissue defining a body cavity, which cannula compriseε interior εurfaces defining a lumen and a distal end having an opening, the trocar asεembly compriεing: a handle; an obturator extending from said handle and having an axis, said obturator comprising: a proximal portion, a firεt distal end portion comprising a base part and surfaces adapted to engage the wall defining the body cavity, detent means for releaεably connecting said proximal portion of said obturator to said first distal end portion of said obturator, said detent means having release restricting means, cooperable with εaid cannula, for reεiεting separation of said proximal and first distal end portions of said obturator when said obturator is placed within the lumen of the cannula; and a second distal end portion compriεing a surfaces adapted to engage the wall defining the body cavity. 10. A kit asεembly according to claim 9 wherein: said first distal end portion has an axial length and said second distal end portion has an axial length which is greater than the axial length of said first distal end portion. 11. A method of using a trocar assembly comprising the stepε of: providing a cannula compriεing interior εurfaces defining a lumen and a distal end having an opening; providing a kit having the trocar assembly comprising a handle, an obturator extending from said handle and having an axis, the obturator comprising a proximal portion, and a first diεtal end portion compriεing a surface adapted to engage a wall defining a body cavity, and detent means for releasably connecting said proximal portion of said obturator to said first distal end portion of said obturator, and a second distal end portion different than said first distal end portion; attaching the first distal end portion to the proximal portion; then placing the obturator within the cannula; inserting the cannula through a wall having tissue defining a body cavity; then removing the used or dull diεtal end portion; and replacing the used or dull distal end portion of the obturator with the εecond diεtal end portion. 12. A method according to claim 11 wherein the step of providing the trocar asεembly comprises the steps of providing a groove part extending about the axis of the obturator located on one of the proximal and distal end portions and a detent part situated on the other of the proximal and distal end portions and adapted to engage the groove part, and the εtep of placing the obturator within the cannula compriεeε the εtep of placing the obturator within the cannula such that at least a portion of the groove part and the detent part are situated within the lumen of the cannula and the surface adapted to engage a wall defining a body cavity project beyond the distal end of the cannula, and such that the interior surfaceε of the cannula reεiεt releaεe of the connection between the proximal portion and the diεtal portion.

Inventors: METCALF GERALD L, REMOND RUSSELL J, VIDAL CLAUDE A, METCALF, GERALD, L., REMOND, RUSSELL, J., VIDAL, CLAUDE, A.
Applicants: MINNESOTA MINING & MFG, MINNESOTA MINING AND MANUFACTURING COMPANY
Application year: 1994
Main classification: A61B17
IPC codes: A61B17